TITLE: GCN CIRCULAR NUMBER: 30663 SUBJECT: Fermi trigger No 651110719: Global MASTER-Net observations report DATE: 21/08/20 00:17:29 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) started inspect of the Fermi GRB210820.00 (trigger No 651110719,17h 39m 14.40s , +65d 21m 00.0s, R=2.77) errorbox 5 sec after notice time and 64 sec after trigger time at 2021-08-20 00:06:18 UT, with upper limit up to 17.0 mag. The observations began at zenith distance = 48 deg. The sun altitude is -46.9 deg. The galactic latitude b = 32 deg., longitude l = 95 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1694987 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 70 | 2021-08-20 00:06:18 | MASTER-IAC | (17h 40m 13.81s , +65d 19m 34.9s) | P| | 10 | 16.0 | 70 | 2021-08-20 00:06:18 | MASTER-IAC | (17h 38m 08.67s , +65d 25m 39.1s) | P- | 10 | 15.8 | 104 | 2021-08-20 00:06:48 | MASTER-IAC | (17h 40m 16.51s , +65d 21m 15.8s) | P| | 20 | 16.5 | 104 | 2021-08-20 00:06:48 | MASTER-IAC | (17h 38m 11.30s , +65d 27m 19.4s) | P- | 20 | 16.4 | 144 | 2021-08-20 00:07:28 | MASTER-IAC | (17h 40m 10.39s , +65d 20m 20.5s) | P| | 20 | 16.5 | 144 | 2021-08-20 00:07:28 | MASTER-IAC | (17h 38m 05.30s , +65d 26m 23.9s) | P- | 20 | 16.4 | 189 | 2021-08-20 00:08:08 | MASTER-IAC | (17h 40m 10.62s , +65d 21m 21.9s) | P| | 30 | 16.7 | 189 | 2021-08-20 00:08:08 | MASTER-IAC | (17h 38m 05.51s , +65d 27m 25.1s) | P- | 30 | 16.8 | 244 | 2021-08-20 00:08:58 | MASTER-IAC | (17h 40m 15.67s , +65d 20m 23.0s) | P| | 40 | 16.9 | 244 | 2021-08-20 00:08:58 | MASTER-IAC | (17h 38m 10.73s , +65d 26m 26.0s) | P- | 40 | 17.0 | The observation and reduction will continue. The message may be cited.